From opposition politicians, the reaction to the speech on the environment by the UK Prime Minister, Tony Blair, has been scornful.

The Conservatives dismissed it as "yet another pre-election stunt", and the Liberal Democrats said the government had failed miserably on the environment.

But Mr Blair has won rare praise from some of his normally fierce critics among the environmental campaigners.

Friends of the Earth said the Prime Minister had "thrown down a green gauntlet to the other party leaders."

FoE's executive director, Charles Secrett, said: "This is the strongest environment speech Tony Blair has yet made. It is welcome evidence of joined-up green thinking in 10 Downing Street. Now we need to see joined-up green action across government."

'Rich deprive poor'

The group welcomed Mr Blair's commitment to act on climate change. He called for the ratification of the Kyoto Protocol, the international climate agreement, by the time the World Summit on Sustainable Development meets in South Africa next year.

Europe's farm crisis "has a silver lining"

But he went much further, acknowledging the scientific case for cutting global carbon dioxide emissions by 60% or more.

Mr Blair also said that sustainable development demanded sustainable food production. Yet several studies showed the rich nations' farming policies continued to impoverish the developing world.

"For us in Europe", he said, "this means summoning up the political will to reform the European Union's common agricultural policy.

"I believe there is the beginning of a new debate in Europe. The opportunity to change direction is the silver lining in the European farming crisis."

FoE welcomed this passage, but said it wanted to see "a clear Government strategy on how it will act at home and in the EU to achieve this shift". And it criticised the speech for being weak on transport, and for failing to make clear that much of the new money being spent here would go on new road schemes.

The conference where Mr Blair was speaking was organised jointly by WWF, the global environment network, and the Royal Institute of International Affairs (RIIA).

'Down payment'

Robert Napier, the chief executive of WWF-UK, said: "There were very strong signals today that the UK Government and Labour are prepared to take meaningful action on the environment."

Wave energy will be boosted

The head of the RIIA's energy and environment programme, Duncan Brack, told BBC News Online: "It was a good speech, certainly an improvement on earlier environment speeches by Mr Blair.

"His commitment to go to the sustainable development summit in Johannesburg is extremely important, and so is his determination to see the Kyoto Protocol ratified by then.

"And saying he will sit down with business leaders in the months beforehand is exactly the sort of thing that needs doing."

Stephen Tindale of Greenpeace described Mr Blair's promise of £100m for renewable energy as "a breakthrough - only a down payment, but a very welcome first step".

"This is the first indication that the Prime Minister is genuinely and personally committed to the fight against climate change", Mr Tindale said. "It's now up to the other parties to follow his lead and outline their plans on climate."